Currently,　applying　graphene　on　GaN　based　electronic　devices　requires　the　troublesome,　manual,　lengthy,　and　irreproducible　graphene　transfer　procedures,　making　it　infeasible　for　real　applications.　Here,　a　semiconductor　industry　compatible　technique　for　the　in　situ　growth　of　patterned　graphene　directly　onto　GaN　LED　epiwafers　for　transparent　heat-spreading　electrode　application　is　introduced.　Pre-patterned　sacrificial　Co　acts　as　both　an　etching　mask　for　the　GaN　mesa　and　a　catalyst　for　graphene　growth.　The　Co　helps　in　catalyzing　the　hydrocarbon　decomposition　and　the　subsequent　graphitization,　and　is　removed　by　wet　etching　afterwards.　The　use　of　plasma　enhancement　in　the　graphene　chemical　vapor　deposition　reduces　the　growth　temperature　to　as　low　as　600　degrees　C　and　improves　the　graphene　quality,　where　highly　crystalline　graphene　can　be　obtained　in　just　2　min　of　deposition.　This　method　reduces　the　exposure　of　the　GaN　epilayers　to　high　temperature　to　its　limit,　avoiding　the　well-known　GaN　decomposition　and　In　segregation　problems.　Importantly,　it　can　directly　pattern　the　graphene　without　using　additional　lithographic　steps　and　in　doing　so　avoids　any　unintentional　deleterious　doping　and　damage　of　graphene　from　contact　with　the　photoresist.　The　approach　simplifies　the　fabrication　and　enables　mass　production　by　eliminating　the　bottlenecks　of　graphene　transfer　and　patterning　procedures.　By　comparing　the　GaN　LEDs　with　and　without　graphene,　we　find　that　graphene　greatly　improves　the　device　optical,　electrical　and　thermal　performances,　due　to　the　high　optical　transparency　(91.74%)　and　high　heat　spreading　capability　of　the　graphene　electrode.　Unlike　transferred　graphene,　this　method　is　intrinsically　scalable,　reproducible,　and　compatible　with　the　planar　process,　and　is　beneficial　to　the　industrialization　of　GaN-graphene　optoelectronic　devices,　where　the　integrated　graphene　serves　as　a　superior　sustainable　and　functional　substitute　to　other　transparent　conducting　materials　such　as　ITO.